#include <stdio.h>
#define _CRT_SECURE_NO_WARNINGS
int main() {
    int n = 0;
    scanf_s("%d", &n);
    double sum = 0;
    for (int i = 1; i <= n; i++)
    {
        double num = (double)1 / i;
        sum += num;
    }
    printf("%lf", sum);
    return 0;
}


